You use the body wash in the bath or shower (i.e. when you are wet)
You use the body lotion after you've dried off, to re-moisturise your skin
Eau de toilette is a sort of perfume
eau de toilette - light version of perfume (watered down)
body lotion - put on after a bath or shower or just when you feel like a bit of moisture on your skin
body wash - liquid soap which usually gets used in the shower
A body wash is used to cleanse your body in the shower or bath. After bathing and drying off your body, then apply the body lotion all over. The body lotion is used to moisturize your skin.